Redundant array of independent disks (RAID) is a data storage virtualization technology that combines a plurality of physical disk drives into a single logical unit for the purpose of improving data redundancy, reliability and performance. Depending on the desired level of redundancy and performance, data is distributed across a plurality of physical disk drives with one of multiple RAID levels, for instance, RAID 0-RAID 50. Taking the conventional RAID 5 as an example, the RAID 5 consists of block-level striping with distributed parity check. Information of parity check is distributed among a plurality of physical disk drives. When a single physical disk drive damages, data that is read subsequently can be calculated based on the distributed parity check (such as through Exclusive OR (XOR) operation) such that no data is lost. At the same time, one hot spare physical disk drive can be selected to replace the damaged physical disk drive. All the data on the damaged physical disk drive will be rebuilt and written into the selected hot spare physical disk drive.
However, as rebuilding time of the traditional RAID technology is limited by the writing input/output bandwidth of the hot spare physical disk drive, writing input/output bandwidth of the hot spare physical disk drive has become a bottleneck for the traditional RAID technology, making it difficult for the traditional RAID technology to reduce the rebuilding time. Therefore, a mapped RAID technology is generated.